when imac is sleeping, fan speed goes high?

[silverwhalle]

i have a 21.5inch imac 2011. it seems to be have a problem with sleep mode.
it's appeared to be operating at more high speed than default value, after i awake it by pressing esc button.

before sleeping it works at default value 1200 rpm. but after awakening from sleep, smc fancontrol show me that it's working at about 1300 or more high speed and then goes to normal state 1200 rpm in a few second.

i think there are two possibilities. first is sleep function works abnormally.
second is that smc fancontrol utility detect incorrectly specifically when awakening from sleep.
what about yours?

 

[Photofan]

I am a bit perturbed by this post because my brand new 27" imac is totally silent - that is the first thing I noticed - surely there should be some fan noise??

 

[silverwhalle]

no fan noise

I am a bit perturbed by this post because my brand new 27" imac is totally silent - that is the first thing I noticed - surely there should be some fan noise??

there's no fan noise. and my imac is also totally silent.
i just wonder if my imac's sleep mode doesn't function correctly.
with my macbook, fan speed goes down when sleeping. and after awakening it goes up to normal speed, but not in the imac i own.

 

[macdudesir]

there's no fan noise. and my imac is also totally silent.
i just wonder if my imac's sleep mode doesn't function correctly.
with my macbook, fan speed goes down when sleeping. and after awakening it goes up to normal speed, but not in the imac i own.

If you don't hear the fans, then its probably just when it wakes from sleep the fans rev real quick I'm guessing from the power surge? My iMac does that too i look at iStat and it reports high fan speeds for about 1 or 2 seconds then they go back to default, is this what your experiencing? If so, its perfectly normal.

 

[silverwhalle]

My iMac does that too i look at iStat and it reports high fan speeds for about 1 or 2 seconds then they go back to default, is this what your experiencing? If so, its perfectly normal.

yes. it's exactly what i experienced. yours too.. thank you.
i wanted to know how it works in the imacs you have.
and i think what you said is closer to the correct answer to this situation.
i wasn't able to think it's caused by power serge..

 

[macdudesir]

yes. it's exactly what i experienced. yours too.. thank you.
i wanted to know how it works in the imacs you have.
and i think what you said is closer to the correct answer to this situation.
i wasn't able to think it's caused by power serge..

Sorry, i guess i should have explained more, its not a power surge to your wall outlet...more a power surge to get the computer going, like some/most cars will idle higher then normal for the first few seconds then the rpms will drop to a normal level...at least thats what I've noticed in my family's cars...but that might actually be only something that happens on boot up...not wake up(the power surge)...hmmm looks like i have something to research tonight lol. either way, my point still stands that what we are experiencing with the fans is perfectly normal and nothing to be worried about...

Edit: i reread your OP and i just wanted to add that the fans do not run during sleep so they can't be high while its sleeping...and i wanted to say sorry if i came off rude, I'm not trying to be by any means...i just reread my post and it could possibly be interpreted as rude...again, I'm not trying to be....